How to calculate length and width of object in binary image using GUI?

Hello everyone, so I have a footprint image in binary image. I want to measure the length and width of those footprint using GUI. I have an idea to do it by calculate the maximum pixel value in row and column of those binary image and show the result in edit text. I know maybe I can use regionprops for measuring maximum pixel value but I still dont understand how to use it. Anyone who know how to do it? Or maybe anyone who can measure the footprint using another way beside using regionprops? please I need help. Thank you